I am using my 8gb card that came with my milestone and lately, it's been acting up. On many occasions, it wont even show up on my phone. it says its unavailable and i get no access to my files. I try restarting the phone and plugging it into the computer through usb and after doing that a few times, it finally shows up and i can access my files. Is this a common problem or should i start looking for a new microSD card?